The article considers lying as an epistemic attitude, analyzes its structural and substantive characteristics. In particular, it considers the pragmatic consequences of using false beliefs, primarily in scientific practice. It is shown that in a number of cases false epistemic attitudes can play a positive role, mainly as temporary hypothetical or counterfactual assumptions, as well as positive illusions. The paper also analyzes two alternative approaches towards false beliefs: “knowledge-first epistemology” of T. Williamson and “action-first epistemology” in line with epistemic pragmatism. (...) It considers the potential of the latter approach and, in particular, the way of reconciling two seemingly conflicting normative frameworks – for beliefs and for actions. This, in turn, opens the way for building a complex normative system with different “directions of fit” between beliefs and actions on one side and the world on the other. (shrink)